Did Minsky and Papert know that multi-layer perceptrons could solve XOR?
There does not appear to be a historical consensus on this.
The Wikipedia page on the Perceptrons book (which does not come down on either side) gives an argument that the ability of MLPs to compute any Boolean function was widely known at the time (at the very least to McCulloch and Pitts).
However, this page gives an account by someone present at the MIT AI lab in 1974, claiming that this was not common knowledge there, alluding to documentation in &quot;Artificial Intelligence Progress Report: Research at the Laboratory in Vision, Language, and other problems of Intelligence&quot; (p31-32) which is claimed to support this.